Hi. I have been a diamond for a year and a gold two years before that. The biggest difference for me is that at mainline/top of line hiltons eg Hilton, Conrad, you will probably be upgraded to a much nicer room or the executive level with access to the executive lounge. I have most enjoyed great upgrades at hotels outside the U.S.

Don't expect much different treatment as a diamond at lower range Hiltons such as Hampton Inn, HGI, Doubletree, Homewood, Embassy.